Liquid chromatographic analysis is an important procedure in chemical testing and analytical work. Liquid chromatographs do a very good job. Substantial labor is required, however, to deliver a large number of small specimens to a chromatograph.
This disclosure is directed to a multi-sample injection apparatus for a liquid chromatograph analyzer. The apparatus of the present invention is installed upstream of a liquid chromatograph to deliver multiple samples. In the analysis of a sample, it is necessary to deliver it to the chromatograph. Delivery of a sample to a chromatograph entails substantial hand labor. The hand labor can, perhaps, be ignored where only one or two samples must be tested. Quite often, a chromatograph is operated to test numerous different samples through the day. This means that the test personnel must operate the equipment many times during the day. With each injection, certain valves must be opened and closed in a set procedure to deliver a sample. The sample is then delivered to the chromatograph, and the test is run.
The foregoing procedure is disruptive and wasteful of test personnel time, energy and effort. More importantly, it fairly well ties test personnel to the chromatograph because they must come back, time and again, to the test equipment to inject the next sample to be tested by contrast, the present invention is an apparatus which enables test personnel to install all of the samples in the apparatus at one time. If, for instance, the test personnel has twelve specimens to be tested, all twelve can be loaded at one time. When all specimens have been loaded, the equipment can then be left untended. The samples are then delivered in sequence for individual tests.
In such a procedure, it is necessary to load the specimens as a group and yet maintain separation between individual specimens. It is not desirable that two specimens, delivered consecutively, run together. Chemical analysis of the mixed specimens would then be incorrect.
The present invention is able to deliver multiple specimens to be tested without slip up. In most valving installations installed on chromatographs, there is a correct sequence of valve operations. If an incorrect sequence is used, sample material can be lost. Sometimes, this is a catastrophic occurrence which cannot be permitted. The present invention is able to operate in a foolproof fashion so that there is no possibility of losing a specimen.